Traction type hoist

ABSTRACT

A traction hoist of the type in which a rope is wound around a drum to provide a plurality of windings in side by side substantially parallel relationship. The shunting of the rope from one winding to the adjacent winding and the tensioning of the rope is accomplished by rollers so as to minimize power loss, provide automatic self-reeving action and to permit either end of the rope to be the tensioned end. Means is provided for indicating the presence of a damaged rope and for automatically shutting off the power in the event such damage is detected.

United States Patent 1191 Arnold Feb. 12, 1974 8/1952 lmshaug 340/259 TRACTION TYPE HOIST 2,606,238 [76] Inventor: Carter H. Arnold, 317 Rocky Point F I PAT N OR AP LIC TI NS R l s Verdes Estates, Calif- 112,967 1/1945 Sweden 254/010. 11 90274 728,622 4/1955 Great Britain 254/DlG, ll

[22] Filed: 1971 Primary ExaminerEvon C. Blunk [21] Appl. No.: 207,374 Assistant ExaminerJames L. Rowland Related US. Application Data I ABSTRACT [63] -Continuation-impart of Ser. No. 69,709, Sept. 4,

970 Pat 3,707,275 A traction hoist of the type in which a rope is wound around a drum to provide a plurality of windings in 52 us. c1 254/150 R, 254/190, 242/4701 Side by Side Substantially Parallel relationship The 51 Int. Cl B66d 1/30 shunting f the p from one winding to the adjacent Field f Search 254/ 50 R, 1 74 75; winding and the tensioning of the rope is accom- 340/259, 260; 242/47.()1, 47,12 P ished by rollers so as to minimize power loss. provide automatic self-reeving action and to permit either 5 References Cited end of the rope to be the tensioned end-Means is pro- UNITED STATES PATENTS vided for indicating the presence of a damaged rope 2 H 2 /I 59 A Id- 254/O R and for automatically shutting off the power in the rno 2,922,623 1/1960 Simmons.. 254/150 R event Such damage is detected 3,052,878 9/1962 Berry 254/174 X 3 Claims, 3 Drawing Figures /4 '4' 109 /4 47 l [/5 /3 4 @1 M5 /05 M0 5; M (0/ A TRACTION TYPE HOIST This application is a continuation-in-part of application Ser. No. 69,709 filed Sept. 4, 1970, now US. Pat. No. 3,707,275.

This invention relates to an improved traction type hoist of the type in which a rope is wound around a drum to provide a plurality of windings in side by side parallel relationship. The invention provides certain improved features over the hoist disclosed in the above noted patent.

The main objects of the present invention are to provide an improved traction hoist of the subject type and also to provide a safety feature whereby the power to the hoist is automatically shut off when the wire rope has a irregularity in its cross section deviating sufficiently from normal to cause damage to the wire rope and to the hoist if the hoist were to continue to operate.

Other objects and advantages will be seen from the following specification and from the drawings:

FIG. 1 is a side elevation of the preferred form of the hoist with the front plate removed to show the structure between the front and rear plates of the hoist.

FIG. 2 is a developed view of one side of the hoist showing the various rollers in the position they take while the hoist of FIG. 1 is being raised.

FIG. 3 is a view similar to FIG. 2 with the rollers omitted and showing the rope in the arrangement it takes when the hoist is being lowered.

The general organization of the hoist housing, the power driven drum, and the arrangement of windings of the rope is generally similar to that disclosed in the above noted copending application and reference may be made to said application for details of construction not set forth herein.

The hoist housing is generally designated 101 and comprises a pair of front and rear side plates 102, 103 between which the drum 104 is rotatably supported and driven by the means indicated in said copending application. The hoist herein described has a drum provided with six grooves but it will be understood that the number of grooves is not critical. In the form shown in FIG. 1 one end 105 of the wire rope is shown extending upwardly from the drum 104 and, as best seen in FIG. 2, said end enters the groove in the drum which is adjacent the front side plate 102. The rope is then wrapped around substantially the entire periphery of the drum until it is engaged by transfer roller 107 which, as best seen in FIG. 2, shunts the rope into the adjacent groove. Again the rope is wrapped around substantially the entire circumference of the drum until it engages transfer roller 108 which urges it into the third groove. Once again the rope is wrapped around substantially the entire circumference of the drum and is then shunted by a third transfer roller 109 into the fourth groove.

The rope in the fourth groove engages the same for about only half the circumference of thedrum until it is shunted into the fifth groove by transfer roller 1 12 at the lower side of the drum 104 as seen in FIG. 1. The rope in the fifth groove then extends around substantially the entire circumference of the drum until it is engaged by transfer roller 111 which shunts it into the sixth groove in which the rope engages for substantially the entire circumference of the drum and then becomes the lower end 106 (FIG. 1).

It will be noted when the hoist of FIG. I is being raised with the drum rotating clockwise the portion of the rope connected with the tail end 106 does not engage the remaining transfer roller which is disposed relative to the points of tangency of ends 105, 106 in the same manner as the first mentioned transfer roller 107. As noted in the copending application one transfer roller is thus inoperative while the hoist is being driven in one direction and a different transfer roller becomes inoperative when the hoist is driven in the reverse direction. In this case when the hoist is being raised transfer roller 110 is inoperative. However as seen in FIG. 3 when the direction is reversed and the hoist is lowered then transfer roller 110 operates to shift the rope from the groove adjacent rear side plate 103 to the next groove. From FIG. 3 it will be seen that in such an event the rope is shunted into the firstgroove by transfer roller 108 and transfer roller 107 then becomes inoperative.

By the present invention it will be seen that transfer rollers 107, 108 and 109 are symmetrical, as a group, with transfer rollers 110, 11, and 112 relative to the points of tangency of the ends 105, 106 of the wire rope. The close positioning of these two sets of upper and lower transfer rollers insures that the first few windings adjacent each end of the rope engage the drum periphery to the optimum extent thus maximizing the traction on the drum and at the same time permitting either end of the rope to be the loaded end. This is extremely desirable in many instances and enhances the versatility of the hoist.

For the purpose of urging the rope against the periphery of the drum and thus increase the traction a plurality of tension rollers having their peripheries yieldably urged against the rope are provided between the transfer rollers 109, 112(FIG. 1). These tension rollers are designated 115-120. In addition, at the points of tan gency of the ends 105, 106 there is provided a tension roller 121 which, it will be noted from FIG. 2 is provided with a plurality of grooves 122 in which the windings of the rope are received. From FIG. 2 it will be apparent that tension roller 121 is the only tension roller that engages the rope in all six grooves of the drum 104. It will be seen that in FIG. 2 the fourth groove is empty for substantially half of its circumference while in FIG. 3 the third groove is empty for substantially half its circumference. For this reason the tension rollers 115 to are not provided with grooves at their central portions as is tension roller 121 but said tension rollers 115-120 are recessed along their central portions as indicated by dot dash lines on transfer roller 121 in FIG. 2. This recessed portion is somewhat less in diameter than the bottom diameter of the grooves 122 so that clearance is permitted for the windings of the rope to move from the fourth groove to the third groove and vice versa.

At this point it will be noted that reversibility of the hoist is provided while at the same time optimum traction is insured by the positioning of the tension rollers above described. 1

The hoist herein described lends itself to self-reeving in a somewhat similar manner as the hoist disclosed in the above noted copending application. However somewhat closer control over the wire is obtained by the herein described transfer rollers and the tension rollers and by certain reeving rollers now to be described;

As seen in FIG. 2 the transfer roller 107 which shunts the rope from the first to the second groove is tilted relative to the drum axis so as to obtain a smooth transition of the rope from the first winding to the second winding. The actual degree of tilt varies with the diameter of the drum and with the diameter of the wire rope. For an 8- /2 inches diameter drum and 5/16 inch diameter wire rope the angle is preferably about 7-/z. To assist in this transition a reeving roller 125 is rotatably mounted on a shaft 126 secured to side plate 103. Said reeving roller 125 is positioned closely adjacent transfer roller 107 and, since it would otherwise interfere with guide 128 of rope end 105 it does not extend across the entire width of the drum and is not supported on front plate 102. This reeving roller 125 is provided with a curved surface 127 at its outer end which engages the end of the rope as the latter is reeved in the direction shown in FIG. 2. By making the angle of tilt of roller 125 about one half the angle of tilt of transfer roller 107 the desired guiding of the rope is achieved. In this manner reeving roller 125 directs the rope into the second groove where it is under the control of the outer end of a similar reeving roller 130. Again, because of the presence of the rope end 105, reeving roller 130 is cantilevered from the side plate 103 and is similarly formed at its outer end to assist in holding the rope in the second groove. It will be seen from'FIG. 2 that both reeving rollers 125 and 130 are provided with additional grooves similar to grooves 122 on tension roller 121 and which additional grooves are adapted to engage the remaining windings during reeving so as to prevent the rope end from taking its natural direction which would be tangentially of the drum 104.

One of the features of the instant hoist is that it may be reeved from either end. Thus if the rope is reeved from the opposite direction it will be seen in FIG. 3 that cantilevered rollers 132, 133 operate in a manner similar to the above described cantilevered rollers 125, 130.

For the purpose of obtaining complete control over the wire as the same is being reeved onto the drum 104 additional reeving rollers are provided at spaced points around the periphery of the drum. These are indicated at 135-139 in FIG. 1.

The above described reeving rollers 121 and 135-139 are rotatably supported on fixed axes and the same are not resiliently urged against the rope because their only function is to insure that the initial reeving step is carried out. For this reason when the hoist is in operation these reeving rollers are not in engagement with the rope and thus are not called upon to resist a great amount of wear and thus may be formed of fairly inexpensive plastic material.

It will be seen that the arrangement of shunt rollers, tension rollers, and reeving rollers around the drum 104 as seen in FIG. 1 insures complete control over the rope during the reeving process and insures maximum traction during operation of the hoist.

Although it should be known to the operator that the hoist should not be operated with damaged rope, nevertheless it is important to guard against damage to the rope and the hoist which might occur if rope having portions of abnormal cross section were employed. For example. if the rope becomes enlarged, unraveled, or cut or otherwise loses its uniform cross section there is a possibility in certain instances that the wire may get between the transfer rollers and the drum causing further damage to the rope. This is particularly possible with the transfer rollers because it is necessary that the same extend at their peripheries well into the grooves of the drum in order to effect proper shunting action. There is therefore a possibility that a transfer roller will pull through any portions of the wire that get between the periphery of the roller and the bottom of the adjacent groove rather than staying on one side of the enlarged annular portion of the transfer roller. In order to detect that portion of a damaged rope that may get between a transfer roller and the drum before it causes further damage and in order to prevent further operation of the hoist with damaged rope the present invention includes a safety device which will now be described.

As can be seen in the copending application the transfer rollers are supported on shafts which extend between the side walls of the hoist. By the present invention the transfer rollers are yieldably urged radially inwardly of the drum in the same manner as the tension rollers of the copending application. As best seen in FIG. 1 a light flexible cable 144 is fixed at one end to a bracket 145 and is reeved about the shaft of transfer roller 109, then about a fair-lead 146, then about the shaft of transfer roller 108, then around a fair-lead 147, then around the shaft of transfer roller 107, and around a fair-lead 148 which guides the other end of the cable upwardly through an apertured plate 149 fixedly secured to the housing. The cable 144 terminates in a socket 150 which is spring urged upwardly by spring 151. Similarly a second cable is provided with a socket 156 which is spring urged upwardly by a spring 157. This cable 155 is guided by a fair-lead 154 to extend around the shafts of transfer rollers 110, 111, 112 in a similar manner and around fair-leads 158, 159. The stationary end of cable 155 is secured to a fixed bracket 161 similar to bracket 145. In order to permit adjustment of the tension in cables 144, 155 the fixed ends may be provided with externally threaded sockets 162 which are received through apertures in the flanges of brackets 145, 161 thereby permitting adjustment of the tension by means of a nut 163 threadedly secured to socket 162. In this manner the tension in cables 144, 155 may be carefully adjusted so as to position the sockets 150, 156 closely adjacent an actuator arm 165 of a switch 166 which may be in the circuit of the motor driving the hoist so as to open said circuit upon engagement of the actuator 165 by either one of the sockets 150, 156. Alternatively the actuator 165 may also be a portion of the trigger mechanism of a rope gripping device such as that disclosed in application Ser. No. 69,711 filed Sept. 4, 1970.

It will be apparent that if a damaged wire or a strand thereof gets under any one of the six transfer rollers such transfer roller will be moved outwardly by the wire rope against the yieldable means urging it inwardly thus relaxing the tension in the associated cable 144 or 155. In this manner the switch 166 or other safety device is actuated to stop the hoist motor or to activate other appropriate safety devices.

One of the important features of the safety mechanism disclosed in FIG. 1 is that since two portions of the cable extend away from the shaft of each transfer roller a particular amount of radially outward movement of the transfer roller will result in about twice the amount of relaxation of the cable tension as would occur if only a one part cable were affected by such movement. In

this manner positive actuation of the trigger or switch arm 165 is insured even upon a slight radial outward movement of a transfer roller.

Another feature of this safety device is that it operates in the desired manner regardless of the number of units with which it is employed. In other words all of the elements whose movement is to be sensed can readily be connected together so that movement of any one element results in the desired actuation. It will also be noted that no difficult adjustment is necessary to properly position the sockets 150, 156; it merely being necessary to turn the screw 163 until the socket 150 or 156 is slightly spaced from the actuator 165.

The above described hoist thus includes positive means for controlling the wire rope at closely spaced points around the entire length of the rope that is in engagement with the drum. It will also be noted that the rollers having special functions with respect to shunting and tensioning also assist in the self-reeving operation. In this connection it will be noted that the transfer rollers in addition to being formed with the annular enlargement for shunting the wire rope are also provided with grooves for engaging other windings of the rope so that at no point is the rope permitted to deviate from the desired path of travel.

I claim:

1. A hoisting device for use with a length of wire rope, either end of which may be loaded, said device comprising:

a drum provided with a plurality of peripherally extending axially spaced grooves in planes at right angles to the axis of said drum,

arate axis and each adapted to shunt said rope from one groove to an adjacent groove,

one end of .said rope extending outwardly of said drum from the groove at one end thereof and the other end of said rope extending outwardly from the groove at the other end of said drum in substantially the same plane as said one end,

means for mounting a first pair of said transfer rollers respectively positioned closely adjacent and on opposite sides of the points at which said ends extend outwardly from said drum, means for mounting a second pair of transfer rollers positioned closely adjacent said first pair respectively and on the sides of said first pair opposite said points,

each roller of said first and second pairs being provided with a single shunting element.

2. A hoisting device according to claim 1 wherein a peripherally grooved tension roller is provided between said first pair of transfer rollers, and wherein additional rollers are provided around the periphery of said drum each with an ungrooved central portion to provide clearance to allow movement of the central windings in said drum from one drum groove to another.

3. A hoisting device according to claim 1 wherein cantilevered reeving rollers are provided between said first pair of transfer rollers and adjacent said ends. 

1. A hoisting device for use with a length of wire rope, either end of which may be loaded, said device comprising: a drum provided with a plurality of peripherally extending axially spaced grooves in planes at right angles to the axis of said drum, a rope formed intermediate its ends to provide a plurality of parallel windings received in said grooves, a plurality of transfer rollers, each mounted on a separate axis and each adapted to shunt said rope from one groove to an adjacent groove, one end of said rope extending outwardly of said drum from the groove at one end thereof and the other end of said rope extending outwardly from the groove at the other end of said drum in substantially the same plane as said one end, means for mounting a first pair of said transfer rollers respectively positioned closely adjacent and on opposite sides of the points at which said ends extend outwardly from said drum, means for mounting a second pair of transfer rollers positioned closely adjacent said first pair respectively and on the sides of said first pair opposite said points, each roller of said first and second pairs being provided with a single shunting element.
 2. A hoisting device according to claim 1 wherein a peripherally grooved tension roller is provided between said first pair of transfer rollers, and wherein additional rollers are provided around the periphery of said drum each with an ungrooved central portion to provide clearance to allow movement of the central windings in said drum from one drum groove to another.
 3. A hoisting device according to claim 1 wherein cantilevered reeving rollers are provided between said first pair of transfer rollers and adjacent said ends. 